Test::Time can be used to test modules that deal with time. Once you
"use" this module, all references to "time" and "sleep" will be
internalized. You can set custom time by passing time => number after
the "use" statement:
use Test::Time time => 1;
my $now = time; # $now is equal to 1
sleep 300; # returns immediately, displaying a note
my $then = time; # $then equals to 301